Cabinet drawer lock

Abstract: A lock system for a container having a first side wall (6) and a second side wall (8). The lock system comprises a first component (4) supported on a first track which defines a path for the first component (4) to move from a closed position to an open position. The lock system comprises a first locking bar (24) movable from a first position to a second position allowing the first component (4) to move along the first track to the open position. The lock system comprises a second component (5) supported on a second track defining a path for the second component to move from a closed position to an open position. A second locking bar (46) is movable from a first position to a second position allowing the second component (5) to move along the second track to the open position. The lock system further comprises a locking mechanism (78) movable along a ramp (92) to a locking position preventing the first locking bar (24) from moving from the first position to the second position and preventing the second locking bar (46) from moving from the first position to the second position so that the first (4) and second (5) components are each locked in the closed position.

Description: FIELD OF THE INVENTION The present invention relates to a lock system for a container and finds particular expression in a cabinet drawer lock for locking all drawers other than a drawer that is open. The lock system of the invention also relates to a cabinet drawer lock for locking all of the drawers of a cabinet at once. BACKGROUND OF THE INVENTION It is common to have a plurality of drawers or shelves in a cabinet or desk. It is often desirable to prevent selected drawers or shelves from being opened while a single drawer is opened. The prevention of the selected drawers or shelves from being opened helps prevent the accidental opening of those drawers or shelves which can lead to the tipping of the cabinet. It is common to use an interlock system between the selected drawers to prevent their opening, such as described in U.S. Patent No. 3,404,929 to Wright et al., U.S. Patent No. 3,866,993 to Dean et al., and U.S. Patent No. 3,881,793 to Anderson. Another example may be found in US-A-4,966,423 which discloses a lock system according to the preamble of claim 1. In this document there is described a cabinet drawer interlock comprising an actuator on each drawer which is engaged by a separate sprocket rotor. A number of locking bars are arranged in end contacting relation and each locking bar has a slot. First and second pawls on each rotor are inserted between the ends of a pair of adjacent locking bars and within a locking bar, respectively, when a first drawer is opened rotating the rotor for that drawer. The remaining closed drawers cannot be opened since the associated locking bars contact the pawl ends on attempted rotor rotation. It is an object of the present invention to provide a more efficient and less complicated cabinet locking system for locking selected drawers or cabinets. It is also desirable to lock all of the drawers or shelves in their closed position to secure the contents thereof from unauthorized personnel. It is common to use a locking system to lock all of the drawers. However, such locking systems usually involve complicated structures and a plurality of moving elements. It is an object of the present invention to provide a locking system which is able to lock all of the drawers or shelves of a cabinet in a more efficient manner. SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a lock system for a container having a first side wall and a second side wall, said lock system comprising: a first component; a first track attached in use to said side walls and supporting said first component, said first track defining a path for said first component to move from a closed position to an open position; a first locking bar movable from a first position in which said first component is prevented from moving along said first track from said closed position to a second position in which said first component is permitted to move along said first track to said open position; a second component; a second track attached in use to said side walls and supporting said second component, said second track defining a path for said second component to move from a closed position to an open position; and a second locking bar movable from a first position in which said second component is prevented from moving along said second track from said closed position to a second position in which said second component is permitted to move along said second track to said open position; the lock system further comprising a movement mechanism and a locking mechanism, said locking mechanism being engaged by a ramped surface of the movement mechanism to move the locking mechanism to a locking position in which said first locking bar is prevented from moving from said first position to said second position and said second locking bar is prevented from moving from said first position to said second position thereby locking said first and second components in said closed positions, characterised in that the ramped surface is rotatable about an axis and upon engagement with the locking mechanism causes the locking mechanism to move in a direction parallel to said axis. According to a second aspect of the present invention there is provided a method of using such a lock system comprising the step of engaging said locking mechanism with the rotating ramped surface of said movement mechanism so that the ramped surface causes said locking mechanism to move to said locking position in a direction parallel to the axis of rotation of said ramped surface. DETAILED DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of a cabinet employing a lock system in accordance with an embodiment of the present invention; FIG. 2 is an exploded view of a lock system embodying the present invention; FIG. 3A is a side view of a first lock bar for use in the lock system of FIG. 2; FIG. 3B is a side view of a second lock bar for use in the lock system of FIG. 2; FIG. 4 is a front view of a rotatable cam for use in the lock system of FIG. 2; FIG. 5 is a side view of a lock system embodying the present invention in an unlocked position; FIG. 6 is a side view of the lock system of FIG. 5 in a locked position; FIG. 7 is a side view of another lock system embodying the present invention; and FIG. 8 is a side view of a helical cam used in the lock system of FIG. 7. DETAILED DESCRIPION OF PREFERRED EMBODIMENT The present invention is best understood upon viewing a preferred embodiment illustrated in FIGS. 1-8. In FIG. 1 is generally shown a cabinet 2 having a plurality of drawers 4 and 5 arranged one above the other. The cabinet 2 employs a drawer locking system for locking selected drawers and/or locking all drawers according to the present invention. It is understood that the present invention is not limited to drawers, but may be used for other moveable components which retract from an open position to a closed position, such as a shelf, and which support one or more objects. Furthermore, the present invention is not limited to just cabinets, but can be used in other container systems which employ one or more retractable components, such as a desk. Thus, in the description to follow a cabinet is taken to be any container having components which retract from an open position to a closed position. In FIG. 1, a rectangular cabinet 2 is shown having a left side surface 6 and a right side surface 8. Side surfaces 6 and 8 preferably have a double wall construction so as to contain the locking system. The cabinet includes a top surface 10 and a bottom surface (not shown). In addition, the cabinet 2 includes a front surface 12 which defines an opening for the drawers 4 and 5 to move from an open to a closed position and vice versa. The cabinet further includes a back surface (not shown) wherein the side, bottom, top, front, and back surfaces are made of a resilient material, such as steel, wood, particle board, plastic, or structural urethane and are attached to each other in a well known manner, such as welding, nuts and bolts, screws, rivets, or adhesives. When the cabinet surfaces are attached, a space for receiving drawers 4 and 5 is defined. The size of the cabinet 2 is chosen according to the task for which it was intended. In the cabinet 2 of FIG. 1, there are shown two drawers 4 and 5. Each drawer 4 and 5 comprises a first side wall 14, a second side wall 16, a bottom surface 18, a front surface 20, and a rear surface (not shown). The surfaces of the drawer are made of a resilient material, such as steel, wood, particle board, plastic, or structural urethane and are attached in a well known manner, such as welding, nuts and bolts, screws, rivets, or adhesives. It is understood that the size, shape, and the number of the drawers or shelves may vary depending on the intended use of the drawers or shelves. The front surface 20 of each drawer 4 and 5 comprise a handle 22 which allows for one to easily to pull a drawer 4 or 5 from a closed position to an open position as shown in the top drawer of FIG. 1. The handle 22 also improves the ease of retracting an open drawer 4 or 5 to its closed position. The top and bottom drawers 4 and 5, respectively, of FIG. 1 are each supported on a pair of well known horizontal tracks attached to the side walls. The cracks defines a path by which the drawers 4 and 5 move from a closed position to an open position and vice versa. Each track comprises a horizontal surface to allow the side edges of bottom surface 18 to slide along the track surface. It is also possible that drawers 4 and 5 have wheels or rollers attached to side walls 14 and 16 and which roll along the track surface. The above-mentioned structure for the drawers 4 and 5 and tracks is well known in the art and it is understood that the present invention would be applicable to other known systems for opening and closing drawers or shelves. An embodiment of the lock system according to the present invention is shown in FIG. 2. The disclosure to follow discusses the lock system structure at the right side of cabinet 2. It is possible that the lock system can be applied to the left side of cabinet 2 as well or to both sides simultaneously. In particular, there is shown a top locking bar 24 which is associated with the top drawer. Top locking bar 24 is made of a sturdy material, such as 16 Ga cold rolled steel, and has a generally rectangular shape of approximately 0.191m x 0.025m x 1.52 x 10 -3 m (7.50" x 1.00" x 0.060"), as shown in FIG. 2. Integrally attached to the top of locking bar 24 is an L-shape contact element 26 having a length along the locking bar of approximately 0.028m (1.122") and a width of approximately 0.015m (0.593"). Contact element 26 is positioned toward the front surface 20 so as to define an adjacent notch 27. Contact element 26 comprises a top flange 28 oriented perpendicular to the locking bar 24 and having dimensions of approximately 0.015m x 6.35 x 10 -3 m x 1.52 x 10 -3 m (0.593" x 0.250" x 0.060"). Note that the lengths of the locking bars are independent of the size of the drawers. Locking bar 24 further includes a bottom flange 30 integrally attached to the bottom and oriented parallel with top flange 28. Bottom flange 30 has a generally rectangular shape having dimensions 0.025m x 6.35 x 10 -3 m x 1·52 x 10 -3 m (1.000" x 0.250" x 0.060"). As seen in FIGS. 2 and 3A, locking bar 24 includes a pair of knobs 32 having a head portion and a neck portion. Knobs 32 are preferably located approximately 0.032m (1.246") and approximately 0.146m(5.746") from the bottom of locking bar 24. Locking bar 24 is slidably attached to right side surface 8 by inserting the knobs 32 in corresponding circular-like openings 34 as indicated by the dashed lines. At the bottom of openings 34 are slots 36 which allow the neck portions of knobs 32 to move therein. Each opening 34 has a diameter of approximately 9.14 x 10 -3 m (0.360") and each slot 36 has a length of approximately 0.025m (1.0") and a width of approximately 6.35 x 10 -3 m (0.250") so as to slidably engage the neck portions of knobs 32. Furthermore, locking bar 24 is coupled to side surface 8 by having a generally rectangular tab 38 inserted through slot 40 located on side surface 8. Slot 40 has a length of approximately 0.042m (1.650") and a width of approximately 3.81 x 10 -3 m (0.150") so as to snugly receive tab 38. Slot 40 is generally parallel to bottom slot 36 and is offset by approximately 0.012m (0.470") from bottom slot 36. Furthermore, the top of slot 40 is located approximately 0.010m (0.413") above the top of bottom slot 36. A spring 42 is attached at one end to an opening of tab 38 and attached at the other end to an opening or slot 44 located on side surface 8. Spring 42 acts as a return spring so as to return top lock bar 24 and knobs 32 to the bottom of slots 36. Spring 42 has a sufficient stiffness that when lock bar 24 moves to the bottom of slot 36 all other locking bars below top locking bar 24 are forced to the bottom of their respective slots. Thus, spring 42 helps prevent all locking bars from being "hung up" in their top vertical position. Once attached to the right side surface 8, the locking bar 24 is able to vertically travel a distance of approximately 0.011m (0.425") from a first position located at the bottom of the slot 36 to a second position located above the first position. Aligned with and below top locking bar 24 is locking bar 46 which corresponds to the drawer located below the top drawer. As seen in FIG. 2, locking bar 46 is similar to top locking bar 24 in shape and in material. As with top locking bar 24, locking bar 46 slidably engages right side 8 via knobs 48 inserted in circular openings 50 and slots 52 having approximately the same dimensions as knobs 32, openings 34, and slots 36, respectively, as shown in FIG. 3B. Knobs 48 are preferably located approximately 0.032m (1.246") and approximately 0.248m (9.746") from the bottom of locking bar 38. Locking bar 46 has dimensions of approximately 0.301m x 0.025m x 1·52 x 10 -3 m (12.0" x 1.0" x 0.06"). Integrally attached to the top of locking bar 46 is an L-shape contact element 54 having a length along the locking bar of approximately 0.028m (1.122") and a width of approximately 0.015m (0.593") . Contact element 54 is positioned away from the front surface 20 so as to define an adjacent notch 56 located nearest the front surface 20. Contact element 54 comprises a top flange 58 oriented perpendicular to the locking bar 46 and having dimensions of approximately 0.011m x 6.35 x 10 -3 m x 1.52 x 10 -3 m (0.437" x 0.250" x 0.060"). Locking bar 46 further includes a bottom flange 60 having a shape and orientation similar to bottom flange 30 of locking bar 24. Once attached to the right side surface 8, locking bar 46 is able to vertically travel a distance of approximately 0.011m (0.425") from a first position located at the bottom of the slot 52 to a second position located above the first position. With the above-described locking bars 24 and 46, it is possible to automatically lock all drawers other than a drawer already opened. This type of locking scenario is accomplished by a locking mechanism associated with each drawer 4 or 5, such as rotatable top cam 62 and bottom cam 64, as shown in FIG. 4. Each cam 62, 64 is made of a resilient material, such as plastic, and is attached to right side surface 8 by pins 66 located below the lowest of the pair of slots 36 and 52. Each pin 66 is located approximately 5.18 x 10 -3 m (0.204") further away from the front surface 20 than the corresponding slot and is located approximately 0.035m (1.387") below the bottom of the nearest slot. Each pin 66 defines the center of curvature for an approximately 90° curved slot 68. Each slot 68 has an inner radius of curvature of approximately 7.52 x 10 -3 m (0.296") and a width of approximately 0.012m (0.454"). The slot 68 is sized and positioned such so that it receives a generally rectangular lug 70 attached to either cam 62 or 64. As seen in FIG. 4, rectangular lug 70 has a length of approximately 7.62 x 10 -3 m (0.300") and a generally rectangular cross-section 72 to be inserted into slot 68. Cross-section 72 has a height of approximately 8.71 x 10 -3 m (0.343") and a width of approximately 9.55 x 10 -3 m (0.376"). Once lug 70 of cam 62 or 64 is inserted into a corresponding slot 68, cam 62 or 64 is capable of rotating by approximately 90°. Rotation of cams 62 and 64 is accomplished by providing an engagement element, such as pin 74, on a side of the drawer 4 or 5 which engages with cams 62 or 64. Pin 74 is located approximately 0.015m (0.605") above the bottom surface 18 of the drawer and approximately 0.127m (5,013") from the front surface 22 of the drawer. Pin 74 engages with cams 62 or 64 by entering a female slot portion 76 positioned at approximately 45° degrees with respect to lug 70. With the above description of the elements of the locking system in mind, one is able to understand one aspect of the present invention by observing the operation of the embodiment of FIGS. 1-6 as the top drawer is opened. In FIG. 5, as top drawer 4 is opened (indicated by horizontal arrow) pin 74 enters slot portion 76. Further movement of top drawer 4 results in pin 74 engaging cam 62 through slot portion 76 resulting in cam 62 rotating counterclockwise by approximately 90°. During this rotation, lug 70 engages the bottom flange 30 of locking bar 24 resulting in locking bar 24 moving upwards as shown by the vertical arrow of FIG. 6. This rotation results in lug 70 rotating from position A, wherein the lug 70 lies in the notch of the locking bar, to locking position B as shown in FIGS 5-6. At locking position B two events occur. In FIG. 6, the slot portion 76 of top cam 62 has rotated to an extent that pin 74 is able to disengage from the slot portion 76. This allows the top drawer 4 to continue on to the open position shown in FIG. 1. The second event occurring at position B is that lug 70 lies directly over the top flange 58 of locking bar 46 of the bottom drawer effectively locking the bottom drawer in the closed position. The locking of bottom drawer 5 is due to the fact that when the pin 74 of bottom drawer 5 engages the bottom cam 64, cam 64 is unable to rotate because lug 70 is unable to move bottom flange 60 of locking bar 46 upwards. This is due to the fact that when lug 70 of the top cam 62 is at position B, locking bar 46 is unable to move vertically. When locking bar 46 is unable to move vertically then bottom cam 64 is unable to rotate the 90° necessary for the slot portion 76 to allow the pin 74 and bottom drawer 5 to continue toward the open position. Consequently, the bottom drawer is effectively locked. Though the above description describes a two drawer system, it is understood that the present invention can be applied to three or more drawers. In such drawer systems, when a particular drawer is opened that drawer's cam and lug will rotate to a locking position which prevents all locking bars below the lug from moving from a first position to a second position. The cams for the drawers below the opened drawer are prevented from moving their respective locking bars and, thus, the drawers below the opened drawer are locked in the closed position. Besides preventing all drawers below the opened drawer from being opened, all drawers above the opened drawer are locked as well. This is understood upon reviewing FIGS. 2 and 6. The locking bars for each drawer or shelf have a combined length which is less than the height of side wall 8. Thus, there is a space between the top of the cabinet 2 and the top flange 28 of top locking bar 24 when locking bar 24 is located at the bottom of slots 36. The space has a vertical length of approximately 0.011m (0.430"). Consequently, when a drawer is opened all locking bars above the drawer are able to vertically move upward a distance of approximately 0.011m (0.425") leaving a space of approximately 1.27 x 10 -4 m (0.005") from the top of the cabinet. Since such a space is less than the width of lug 70 of the cams associated with the locking bars above the opened drawer, those lugs 70 are unable to move between the locking bars. The inability of the lugs 70 to move the locking bars prevents the cams to rotate and, thus, the drawers associated with the immovable cams and above the opened drawer are locked in the closed position. Another aspect of the present invention is shown in FIGS. 2 and 7. FIGS. 2 and 7 illustrate a second locking mechanism 78 which moves from a first position C to a locking position D (FIG. 7). At position C, top locking bar 24 and bottom locking bar 46 are each able to move vertically from a first position to a second position so that the drawers can be opened and locked as described previously. However, when second locking mechanism 78 moves along a direction approximately 90° with respect to the direction of movement of top locking bar 24 to locking position D, the top locking bar 24 and bottom locking bar 46 are each prevented from moving from a first position to a second position. As mentioned previously, when a locking bar is unable to move the corresponding drawers are locked in the closed position. Thus, when locking mechanism moves to locking position D all of the drawers are effectively locked. Second locking mechanism 78 is approximately rectangular in shape. Locking mechanism 78 comprises slots 80 which engage pins of right side surface 8. Pins 82 are located approximately 0.016m (0.625") from the top of surface 8 and approximately 6.71 x 10 -3 m (0.264)and 0.058m (2.268") from the front of surface 8. A spring 84 is attached to both the locking mechanism 78 and surface 8 as shown in FIGS. 2 and 7. Spring 84 forces locking mechanism 78 to position C in which pins 82 engage the closed ends 86 of slots 80. At position C, a tab 88 of locking mechanism 78 is positioned over notch 27 of locking bar 24. Furthermore, a notch 90 of locking mechanism 78 is spaced above top flange 28 of locking bar 24. At position C, the notch 90 allows the top and bottom locking bars 24 and 46 to move from a first position to a second position and, thus, operate as described previously. Locking mechanism 78 is moved to locking position D (dashed lines), by having the locking mechanism ride along a movement mechanism having a ramped surface, such as helical cam activator 92 engaging an inner curved surface 94 of locking mechanism 78. The ramped surface engages the locking mechansim causing the ramped surface and the locking mechanism to move relative relative to one another. The relative movement is such that the locking mechanism 78 translationally moves a distance which is less than the distance traveled on the ramped surface. This can be seen in FIG. 7, wherein clockwise rotation of helical cam activator 92 about an axis results in curved surface 94 riding along the ramped cam activator surface such that locking mechanism 78 travels parallel or along the axis to position D. Though the embodiment of FIG. 7 discloses pulling the locking mechanism 78 from right to left towards the door, it is understood that the locking system would work equally well if position C was located to the left of position of positiion B and one used the cam activator 92 to push locking mechanism 78 away from the door in a left to right manner. Helical cam activator 92 is made from sturdy material, such as plastic, zinc die cast, aluminum or forged steel. As shown in FIG. 8, activator 92 has a linear surface 96 and a helical ramp surface 98 which rises above the linear surface 96 by approximately 0.013m (1/2") within a rotation of approximately 102°. It is understood that other shapes for the ramp surface are possible so that rotation of the activator results in the locking mechanism 78 to ride along the ramp to the locked and unlocked positions. Activator 92 comprises a cylindrical support 100 which contains an opening 102. Opening 102 receives a bolt 104 which is connected to key mechanism 106, shown in FIG. 2. Key mechanism 106 is contained in a cylindrical portion 108 of a mounting 110 which is attached to the front surface 20 of top drawer 4. Mounting 110 comprises a rectangular portion 112 having openings 114. Mounting 110 is attached to top drawer 4 via screws inserted through openings 114 and into drawer 4. Mounting 110 preferably is made of a resilient material, such as plastic, zinc die cast, forged steel, die cast aluminum. With the above-described lock system, one locks all of the closed drawers by inserting key 106 into the key mechanism 96 which is accessible from opening 108 in drawer 4. One then rotates the key 106 clockwise which results in the helical cam activator 84 engaging and moving the lock mechanism 70 to lock position B as described previously. While the invention has been described with relation to certain presently preferred embodiments, those with skill in this art will recognize other modifications of the invention which will still fall within the scope of the invention, as expressed in the accompanying claims.

Claims: A lock system for a container (2) having a first side wall (6) and a second side wall (8), said lock system comprising: a first component (4); a first track attached in use to said side walls (7,8) and supporting said first component (4), said first track defining a path for said first component (4) to move from a closed position to an open position; a first locking bar (24) movable from a first position in which said first component (4) is prevented from moving along said first track from said closed position to a second position in which said first component (4) is permitted to move along said first track to said open position; a second component (5); a second track attached in use to said side walls (7,8) and supporting said second component (5), said second track defining a path for said second component (5) to move from a closed position to an open position; and a second locking bar (46) movable from a first position in which said second component (5) is prevented from moving along said second track from said closed position to a second position in which said second component (5) is permitted to move along said second track to said open position; the lock system further comprising a movement mechanism (92) and a locking mechanism (78), said locking mechanism (78) being engaged by a ramped surface (98) of the movement mechanism (92) to move the locking mechanism (78) to a locking position (D) in which said first locking bar (24) is prevented from moving from said first position to said second position and said second locking bar (46) is prevented from moving from said first position to said second position thereby locking said first and second components (4,5) in said closed positions, characterised in that the ramped surface (98) is rotatable about an axis and upon engagement with the locking mechanism (78) causes the locking mechanism (78) to move in a direction parallel to said axis. The lock system of claim 1, wherein one or both of said first and second components (4,5) comprises a drawer. The lock system of claim 1, wherein one or both of said first and second components (4,5) comprises a shelf. The lock system of claim 1, wherein, upon engagement with the ramped surface (98), said locking mechanism (78) moves translationally a distance which is less than the distance travelled by said locking mechanism (78) on the ramped surface (98). The lock system of claim 1, wherein said locking mechanism (78) moves in a direction approximately at right angles with respect to the direction of movement of said first locking bar (24). The lock system of claim 5, wherein said locking mechanism (78) is moveable from an unlocked position (C) to said locking position (D), and in said unlocked position (C) said locking mechanism (78) allows said first locking bar (24) to move from said first position to said second position so that said first component (4) may move to said open position. The lock system of claim 6, wherein said locking mechanism (78) comprises a tab (88) to engage said first locking bar (24) when said locking mechanism (78) is in said locking position (D) preventing said first locking bar (24) from moving from said first position to said second position and thereby locking said first and second components (4,5) in said closed positions. The lock system of claim 7, wherein said locking mechanism (78) comprises a notch (90) allowing said first locking bar (24) to move from said first position to said second position when said locking mechanism (78) is in said unlocked position (C). The lock system of any preceding claim wherein said movement mechanism (92) comprises a helical cam activator. A method of using the lock system of claim 1 comprising the step of engaging said locking mechanism (78) with the rotating ramped surface (98) of said movement mechanism (92) so that the ramped surface (98) causes said locking mechanism (78) to move to said locking position (D) in a direction parallel to the axis of rotation of said ramped surface (98). The method of use of claim 10, wherein the step of moving said locking mechanism (78) includes moving said locking mechanism (78) translationally a distance which is less than the distance travelled by said locking mechanism (78) on the ramped surface (98). The method of use of claim 10, wherein the step of moving said locking mechanism (78) includes moving said locking mechanism (78) in a direction approximately at right angles with respect to the direction of movement of said first locking bar (24). The method of use of claim 10, wherein the step of moving said locking mechanism (78) includes moving said locking mechanism (78) from an unlocked position (C) to said locking position (D), such that when said locking mechanism (78) is in said unlocked position (C) said locking mechanism (78) allows said first locking bar (24) to move from said first position to said second position enabling said first component (4) to move to said open position. The method of use of any of claims 10 to 13 and comprising the step of activating a helical cam activator (92) to move said locking mechanism (78).

Inventors: DAME PAUL G, MCCLUNG DUANE G, DAME, PAUL G., MCCLUNG, DUANE G.
Applicants: MILLER HERMAN INC, HERMAN MILLER, INC.
Application year: 1994
Main classification: E05B65
IPC codes: E05B65